1. Field of the Invention
This invention relates to an illuminated controller, and more specifically to an illuminated membrane potentiometer for use as a light dimmer or other voltage controlling device.
2. Description of the Related Art
Potentiometers are well known for controlling voltage selection in numerous types of applications in both home and industry. For example, these devices may be used in the control panels of such things as aircraft and aerospace applications, computers, arcade games, kitchen appliances, or lighting systems to name a few.
In the past, prior art potentiometers for providing voltage selection have typically been operated using a mechanical wiper that is typically controlled by a knob or slider on a control panel. The wiper contacts a resistive element, which provides for voltage selection over a continuous range of voltages. The constant mechanical contact between the wiper and the resistive element tends to accelerate the wear and eventual failure of this type of potentiometer.
A more recently devised potentiometer uses a membrane comprising a continuous length of electrically resistive material, a corresponding continuous length of electrically conductive material, which serves as a wiper, and an electrically insulating spacer which serves to simultaneously support and separate the resistive and conductive layers. Either one or both of the resistive and conductive materials are designed as flexible members so that they can be pressed together at any selected location along their length to bring them into electrical contact.
If a voltage is applied across the resistive material, a voltage gradient is established along the length of the material. Thus, touching either the top or bottom surface of the flexible member will cause the resistive and conductive materials to contact each other, producing a voltage output on the conductive material or wiper. The advantage of this device is that it minimizes wiper contact and reduces wear and yet provides a continuous range of output voltage levels.
A potentiometer membrane as described can be used to make a reliable and economical dimmer and/or switch for use with a light fixture. However, since light switches and dimmers and other potentiometer controls must sometimes be found and used in poorly lit rooms, it is desirable to provide an illumination source on the control. Accordingly, it is known in the prior art to place an L.E.D on a potentiometer control (U.S. Pat. No. 4,962,364 to Okuya) or to use a photo-conductive element routed to the control knob surface (U.S. Pat. No. 4,523,174 to Oyama). However, these devices are only illuminated by a small point source of light. It is desirable to have a larger surface of the potentiometer illuminated so that it will be easier to see and softer on the eyes.
3. Related Art
Examples of patents that are related to the present invention are as follows, and each patent is herein incorporated by reference for the supporting teachings:
U.S. Pat. No. 5,241,308 is a force sensitive touch panel.
U.S. Pat. No. 5,228,562 is a membrane switch and fabrication method.
U.S. Pat. No. 5,962,364 is an illuminating type linear resistor for volume control.
U.S. Pat. No. 4,939,501 is a sliding foot controller.
U.S. Pat. No. 4,725,817 is a pressure responsive panel.
U.S. Pat. No. 4,542,366 is an illuminated variable resistor.
U.S. Pat. No. 4,523,174 is an illumination type rotary variable resistor.
U.S. Pat. No. 4,494,105 is a touch controlled circuit apparatus for voltage selection.
U.S. Pat. No. 4,017,848 is a transparent keyboard switch and array.
U.S. Pat. No. 4,005,381 is a slide potentiometer.
U.S. Pat. No. 3,968,467 is a touch controlled voltage-divider device.
U.S. Pat. No. Re. 33,089 is a position sensing and indicating device.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information which may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.